A veteran of Chicago politics, Alter has known President Obama and his closest confidantes for as long as nearly any national columnist, having published the first national magazine cover story on Obama in Newsweek’s 2004 “Who’s Next Issue.”[3]

For a decade in the 1980s, Alter was Newsweek'smedia critic, where he was among the first in the mainstream media to break tradition and hold other news organizations accountable for their coverage,[citation needed] a precursor to the role later played by blogs. When Newsweek launched his wide-ranging column in 1991, it was the first time the magazine allowed regular political commentary in the magazine, other than on the back page. After the election of Bill Clinton in 1992, during which Alter was a consultant to MTV, he was among a small group of reporters and columnists who had regular access to Clinton, though he was far from a reliable supporter, particularly during the Monica Lewinsky scandal. "Alter bites me in the ass sometimes, but at least he knows what we're trying to do," Clinton was quoted as saying in the book Media Circus by The Washington Post'sHoward Kurtz.

Alter gained international notoriety on election night 2000, when on NBC with Tim Russert and Tom Brokaw, he claimed that the election would be settled in court. He was the first pundit to predict the months long recount process.[13]

Two months after the September 11 attacks, Alter wrote an article for Newsweek called "Time to think about torture" which became one of his best-known articles.[14] In the column, he suggested that the U.S. might need to "rethink ... old assumptions about law enforcement". Stating that "some torture clearly works", he suggested the nation should "keep an open mind about certain measures to fight terrorism, like court-sanctioned psychological interrogation", and consider transferring some prisoners to other countries with less stringent rules on torture.[15]

Alter was a fierce critic of President George W. Bush,[citation needed] emphasizing what he considered Bush's lack of accountability and his position on embryonic stem cell research. Alter, a cancer survivor, has written about his own bout with lymphoma and experience with an autologous adult stem cell transplant.[16] On NBC's Today Show, Alter was the correspondent for several stories about the effect of the Iraq War on returning veterans. The Defining Moment, which was reviewed respectfully, surprised some critics with its analysis which concluded that the United States had come very close to dictatorship before Franklin D. Roosevelt became president, painting him as the savior of American democracy and capitalism. During an interview with 60 Minutes on November 14, 2008, then-President-electBarack Obama said he had recently been reading The Defining Moment and hoped to apply some of Roosevelt's strategies that were outlined in the book into his own administration.[17]

A longtime proponent of education reform, Alter played a major role in the Academy Award nominated documentary Waiting for "Superman".[18] He also sits on the Board of Directors of The 74, an education news website.[19]

Alter is an executive producer of the Amazon Studios show Alpha House starring John Goodman. Written by Doonesbury creator Garry Trudeau, the comedy series revolves around four Republican U.S. Senators who live together in a townhouse on Capitol Hill. After developing the script with Trudeau, Alter sold the pilot to Amazon, which picked up the show as its first original series.[22] The eleven-episode first season began streaming online in late 2013. Production for the second season of Alpha House began in the summer of 2014.[23]

Alter's family has had wide-ranging influence in politics. His mother, Joanne, was the first woman elected to public office in Cook County, Illinois. His sister Jamie Alter Lynton and brother-in-law Michael Lynton, the CEO of Sony Corporation of America, are two of the most politically active fundraisers in California, one cousin Charles Rivkin is one of the creators of the "Muppets" franchise[24] and a former United States Ambassador to France and another cousin Robert S. Rivkin is Chief counsel for the US department of Transportation.[24] Rivkin's wife Cindy S. Moelis is the head of the White House Fellows Program and one of Michelle Obama's closest friends. Alter serves on the Board of Directors of DonorsChoose,[25] which allows teachers to post online proposals for classroom materials, and The Blue Card,[26] a national Jewish organization assisting Holocaust survivors.